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SECUNDARIA - 2º ESO - EX. VELOCITY - PHYSICS & CHEMISTRY - FORMACIÓN

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Subido el 22 de marzo de 2020 por Cp santodomingo algete

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Since now we have the basic concepts of kinematics, let's try now to apply them. 00:00:01
In this video we are dealing with some very simple problems just to practice. 00:00:23
For this is the kind of problems I will ask you to solve in the exam. 00:00:30
We can start with changing the units of velocities. 00:00:36
For example, from kilometers per hour into meters per second. 00:00:41
We multiply 1000 times and we divide 3600, because one hour has 3600 seconds. 00:00:48
So 36 kilometers per hour is the same as 10 meters per second. 00:01:02
Conversely, to pass from meters per second to kilometers per hour, we just multiply 3600 00:01:11
and divide by 1000, so in fact we multiply by 3.6, thus 20 meters per second is the same 00:01:24
as 72 kilometers per hour. 00:01:35
should practice this for the exam. Another typical exercise about velocity 00:01:41
is finding the point where two mobiles meet. To do this, we are just dealing with 00:01:49
mean velocities. In this case, two trains, one leaving Madrid, the other one 00:01:57
Zaragoza, both at the same time, the one from Madrid at a speed of 200 km per hour 00:02:07
and the one from Zaragoza at 150 km per hour, must meet at a certain point 00:02:14
and that point is just the purpose of this exercise, finding it. 00:02:22
Let's just remember that speed is the relationship between space and time. 00:02:28
On the other hand, we know that when the two trains meet, the time will be the same for both. 00:02:36
So we can derive the formula for time and then make both times the same number. 00:02:44
And so we have obtained the key equation where S1 is the space between Madrid and the meeting point, 00:02:53
s2, the distance from Zaragoza up to the meeting point, and v1, v2, their respective velocities. 00:03:03
We can solve this, provided we know the total distance between Madrid and Zaragoza. 00:03:13
In order to do this, we remove one variable using the given value of the total distance. 00:03:21
Thus, we can write. 00:03:29
this equation we have only one variable that we can derive just by multiplying 00:03:34
in cross. Please try to follow this by writing on a paper by yourself. Now we 00:03:40
can group the terms having S1 on the left side of the equation and so we can 00:03:55
derive the value for S1. This means that the trains meet at 200 kilometers away from Madrid. 00:04:03
Of course we can also calculate at what time and since the velocity for train 1 is 200 kilometers 00:04:17
per hour, it's clear that it has spent just one hour. Well, that's all for the moment. 00:04:28
Try to practice, write me your hands on it up, and watch the Padlet where I'm uploading 00:04:39
an exercise that I expect you to send me back before Wednesday. 00:04:47
Subido por:
Cp santodomingo algete
Licencia:
Reconocimiento - Compartir igual
Visualizaciones:
218
Fecha:
22 de marzo de 2020 - 21:31
Visibilidad:
Público
Centro:
CP INF-PRI SANTO DOMINGO
Duración:
04′ 57″
Relación de aspecto:
1.78:1
Resolución:
1280x720 píxeles
Tamaño:
19.73 MBytes

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